Stereo recording techniques capture a sound source with two microphones so the playback has width, depth and a sense of space, rather than a flat mono image. The right technique depends on the source, the room, and how wide and mono-compatible you need the result to be. This guide covers the five methods worth knowing — XY, ORTF, spaced pair (A/B), Mid-Side and Blumlein — and when to reach for each.
Why use stereo recording techniques at all?
A single mic gives you mono: solid and reliable, but with no left-to-right placement. Stereo recording techniques use the small differences between two mic signals — differences in level, timing, or both — to recreate where sounds sit across the stereo field. That width is why a well-recorded acoustic guitar or a drum overhead pair sounds three-dimensional instead of stuck in the middle.
Before you commit to a method, decide two things: how wide you want the image, and whether the recording must stay mono-compatible (important for podcasts, club systems and phone speakers). Coincident techniques like XY collapse to mono cleanly; spaced pairs can suffer phase cancellation. If you are still getting your levels right, read our guide to gain staging first.
Coincident: XY and Blumlein
Coincident techniques place two microphone capsules as close together as possible, angled apart. Because the capsules share almost the same point in space, there is no timing difference between them — the stereo image comes purely from level differences. This makes them the most mono-compatible techniques.
- XY uses two cardioid mics with capsules stacked vertically, angled 90–135 degrees apart. It is forgiving, easy to set up, and rock-solid in mono. The trade-off is a narrower, slightly less dramatic stereo image.
- Blumlein uses two figure-8 mics crossed at 90 degrees. It captures a wide, lifelike image with lots of room sound, because the rear lobes pick up reflections. It needs a good-sounding room and proper figure-8 microphones (often ribbons or multi-pattern condensers).
Near-coincident: ORTF
ORTF splits the difference. Two cardioid mics are spaced 17 cm apart with capsules angled 110 degrees outward. The small spacing introduces gentle timing differences on top of the level differences, giving a wider, more natural image than XY while staying reasonably mono-friendly. It roughly mimics the spacing and angle of human ears, so it is a favourite for acoustic guitar, choirs and room recording.
Spaced pair (A/B) and Mid-Side
A spaced pair places two mics (often omnidirectional) a metre or more apart, pointing at the source. The result is the widest, most enveloping image, with a lovely sense of depth — but timing differences between the mics can cause phase issues, and it is the least mono-compatible technique. Use the 3:1 rule: the mics should be at least three times as far from each other as each is from the source.
Mid-Side (M/S) uses a forward-facing cardioid (or omni) as the “mid” and a sideways figure-8 as the “side”, decoded into left and right. Its killer feature is adjustable width after recording — turn up the side channel for more width, down for more focus — and it is perfectly mono-compatible. It is the technique of choice when you are not sure how wide you will want things in the mix.
Level, timing and how the image is built
Every stereo technique works by feeding your ears one of two cues, or a blend of both. Level (intensity) differences happen when one mic is louder than the other because the capsules face different directions — this is what coincident pairs like XY and Blumlein rely on. Timing (phase) differences happen when sound arrives at one mic slightly before the other because the capsules are physically apart — this is what spaced pairs rely on. Near-coincident methods such as ORTF use a little of each, which is why they tend to sound natural while still imaging well.
Understanding this also explains the risks. Pure level-difference setups stay rock-solid when summed to mono, because both mics hear the same arrival time. Timing-difference setups can partially cancel when summed, thinning the sound or scooping the low-mids. That is the single most important trade-off to keep in mind: wider and more enveloping usually means less mono-safe, and vice versa.
Setting up a pair step by step
Once you have chosen a technique, a consistent setup routine gets you a usable image quickly:
- Mount both mics on one bar. A stereo bar on a single stand keeps the angle and spacing fixed, so you can move the whole array without rebuilding the geometry.
- Set the angle and spacing first. Dial in the textbook starting point for your method — 90 degrees for XY, 17 cm and 110 degrees for ORTF — before you worry about distance to the source.
- Position the array, then audition in mono. Sum both channels and listen: if the sound goes hollow or thin when mono’d, you have a phase problem to fix before tracking.
- Adjust distance for the balance of direct sound to room. Move closer for a tighter, drier image; pull back for more air and ambience. Small moves make a big difference.
- Check your levels. Both channels should sit at a healthy, matched recording level with headroom to spare. Uneven gain pulls the image off-centre.
Common mistakes to avoid
- Ignoring mono compatibility. A spaced pair that sounds glorious on headphones can fall apart on a phone speaker. Always check the mono fold-down if the audio might be heard in mono.
- Mismatched gain between channels. If one mic is louder, the whole image drifts toward that side. Match the input gains before you start, not in the mix.
- Breaking the 3:1 rule. With spaced pairs, mics too close together relative to the source invite comb filtering. Keep the spacing at least three times the source distance.
- Too much spacing for the room. A wide spaced pair in a small, reflective room captures more bad room than width. In a tight space, a coincident or near-coincident pair usually serves you better.
- Forgetting the centre. Very wide setups can leave the middle of the image feeling weak. A spot mic or a narrower technique can firm up the centre when it matters.
Choosing a technique for your source
| Source | Good starting technique |
|---|---|
| Acoustic guitar | XY or ORTF, around 30 cm out |
| Drum overheads | XY or spaced pair |
| Piano | Spaced pair or ORTF |
| Room / ambience | Blumlein or spaced omnis |
| Solo voice with width control | Mid-Side |
Whichever you choose, matched microphones help — two of the same model with similar response keep the image balanced. For pairing techniques with mic types, see our explainer on large vs small diaphragm condensers and the rundown of microphone polar patterns. If you want a deeper walkthrough of running a two-mic array, see how to record with two microphones. For more hands-on capture advice, browse the full recording techniques hub or our walkthrough on recording acoustic guitar.
Frequently asked questions
Which stereo recording technique is best for beginners?
XY is the most forgiving. Two cardioids, capsules together, angled about 90–110 degrees apart — it is hard to get wrong and always sounds fine in mono, so it is the safest first technique to learn.
Do I need two identical microphones?
Ideally yes. A matched pair keeps the tonal balance even across the stereo field. You can mix two different mics, but expect the image to lean tonally toward whichever mic is brighter or louder.
What is the 3:1 rule in stereo recording?
For spaced pairs, keep the distance between the two mics at least three times the distance from each mic to the source. This minimises phase cancellation when the two signals are combined, keeping the recording clean and mono-compatible.
Can I record in stereo with just one microphone?
Not in a true coincident or spaced sense — genuine stereo needs two capsules so the playback carries level or timing differences. A single mic gives you mono. Some mics house two capsules in one body for XY or M/S, but that is still two capsules doing the work.
Why does my stereo recording sound thin when played in mono?
That is phase cancellation, and it usually points to a spaced or near-coincident setup where the two mics capture the same sound at slightly different times. Switch to a coincident technique like XY, tighten the spacing, or check the mono fold-down while you position the mics.
